/*
 * Copyright 2002-2010 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.beans.factory.support;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;

/**
 * Extension to the standard {@link BeanFactoryPostProcessor} SPI, allowing for
 * the registration of further bean definitions <i>before</i> regular
 * BeanFactoryPostProcessor detection kicks in. In particular,
 * BeanDefinitionRegistryPostProcessor may register further bean definitions
 * which in turn define BeanFactoryPostProcessor instances.
 *
 * @author Juergen Hoeller
 * @see org.springframework.context.annotation.ConfigurationClassPostProcessor
 * @since 3.0.1
 */

/**
 * 继承自BeanFactoryPostProcessor，是一种比较特殊的BeanFactoryPostProcessor。
 * 从名字上来看, 这个接口是BeanDefinitionRegistry的后处理器,
 *
 * @see BeanDefinitionRegistry
 * BeanDefinitionRegistryPostProcessor#postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry)方法。
 * <p>
 * 允许在BeanFactoryPostProcessor被调用之前对BeanDefinition做一些操作,
 * 尤其是它可以注册BeanFactoryPostProcessor的BeanDefinition.
 * 它提供了一个方法postProcessBeanDefinitionRegistry(), 可以让我们实现自定义注册bean定义的逻辑
 * 这个方法被调用的时候,所有的BeanDefinition已经被加载了, 但是所有的Bean还没被创建.
 * <p>
 * 注意:
 * <p>
 * 所有的Bean生成都有个顺序: 定义 --> 创建 --> 初始化.
 * BeanDefinitionRegistryPostProcessor的postProcessBeanDefinitionRegistry方法在Bean被定义但还没被创建的时候执行.
 * BeanFactoryPostProcessor的postProcessBeanFactory方法在Bean被创建但还没被初始化的时候执行
 */
public interface BeanDefinitionRegistryPostProcessor extends BeanFactoryPostProcessor {

    /**
     * Modify the application context's internal bean definition registry after its
     * standard initialization. All regular bean definitions will have been loaded,
     * but no beans will have been instantiated yet. This allows for adding further
     * bean definitions before the next post-processing phase kicks in.
     * <p>
     * 在标准初始化之后，修改应用程序上下文内部 已经注册的 BeanDefinition。
     * 所有常规 BeanDefinition 都将被加载，但是还没有被实例化。
     * 这允许在下一个后处理阶段开始之前添加更多的 BeanDefinition。
     *
     * @param registry the bean definition registry used by the application context
     * @throws org.springframework.beans.BeansException in case of errors
     */
    void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException;

}
